Communication between multiple tabs, using local storage changes

gistfile1.js

// User has 2 tabs open: Page 1 and Page 2, both in the same domain
// , subdomain and protocotol

// Page1: https://subdomain.domain.com
...
var data = {
  a: 5,
  // Local storage won't be triggered unless the value is different,
  // so we add a random identifier.
  id: Math.floor((Math.random()*1000)+1)
};
localStorage.setItem('connected', JSON.stringify(data))
...

// Page2: https://subdomain.domain.com
...
var onStorage = function(data) {
  
   if (data.key == 'connected') {
     try {
       var message = JSON.parse(data.newValue);
       console.log(message.a); => 5
     } catch (e) {
       // Invalid JSON     
     }
   }
  
};
...